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Higher microbial biomass accumulation on El Médano 464 meteorite compared with adjacent soils in the Atacama Desert
No full textChondritic meteorites can be appropriate substrates for the colonization of terrestrial microorganisms. However, determining whether organic compounds are intrinsic to the meteorite or come from external (terrestrial) contamination is still controversial. This research explores the molecular distribution and carbon isotopic composition of three lipid families (hydrocarbons, alkanoic acids, and alcohols) as well as DNA extracted from the interior of a CO carbonaceous chondrite named El Médano 464 (EM 464), discovered in the Atacama Desert in 2019. Three soil samples from the discovery area of EM 464 were collected and used as a background control for the composition and distribution of organic compounds. Our results revealed a higher abundance of the three lipid families in EM 464 compared with the surrounding soil samples. The organic compounds in EM 464 showed a mean δ13C value of –27.8 ± 0.5 for hydrocarbons (N = 20), –27.6 ± 1.1 for alkanoic acids (N = 17), and –27.5 ± 2.2‰ for alcohols (N = 18). These δ13C-depleted values are compatible with terrestrial biosignatures and are within isotopic values produced as a result of carbon fixation due to the Calvin cycle (δ13C of ca. from −19 to −34‰) widely used by photosynthetic terrestrial microorganisms. The DNA analysis (based on the bacterial 16S rRNA gene) showed a dominance of Proteobacteria (now Pseudomonadota) and Actinobacteriota in both meteorite and soils but exhibited different bacterial composition at the family level. This suggests that the microbial material inside the meteorite may have partially come from the adjacent soils, but we cannot rule out other sources, such as windborne microbes from distant locations. In addition, the meteorite showed higher bacterial diversity (H’ = 2.4–2.8) compared with the three soil samples (H’ = 0.3–1.8). Based on the distribution and δ13C value of organic compounds as well as DNA analysis, we suggest that most, if not all, of the organic compounds detected in the studied CO chondrite are of terrestrial origin (i.e., contamination). The terrestrial contamination of EM 464 by a diverse microbial community indicates that Atacama chondrites can offer distinctive ecological conditions for microorganisms to thrive in the harsh desert environment, which can result in an accumulation of microbial biomass and preservation of molecular fossils over time
A dynamic hydro-economic model to assess the effectiveness and economic benefits and costs of wetland restoration and creation
No full textThis paper studies the environmental and socioeconomic performance and sustainability of wetland creation/restoration in agricultural watersheds under nonstationary climatic conditions. To this end, we develop a dynamic hydroeconomic modeling framework that integrates the Soil and Water Assessment Tool Plus (SWAT+), Positive Mathematical Programming (PMP), and economic valuation via the benefit transfer method to calculate the effectiveness (wetland area), benefits (economic value of wetland expansion) and costs (foregone agricultural profit) of wetland creation/restoration. Methods are illustrated with an application to the Flumen Watershed wetland restoration and construction project in NE Spain. Results highlight significant tradeoffs between environmental (wetland) and economic (agriculture) water uses, which aggravate over time and are particularly relevant under more severe climate change scenarios. Despite the growing costs and decreasing benefits of wetland creation/restoration due to reduced water availability and wetland surface under climate change, our results show that total wetland benefits over the series offset total wetland costs under all simulations and scenarios. Only during the last years of the series and for the most pessimistic climate change scenarios and combinations of models, costs start exceeding benefits. These results suggest a positive and robust performance of the wetland restoration and creation project in the Flumen Watershed
Nutrients on the move: Investigating large scale fatty acid exports from European ponds via emerging insects
No full textPermanent ponds are key landscape units that supply various ecosystem services. Notably, the export of aquatic subsidies to land via emerging insects may significantly influence terrestrial food webs. Polyunsaturated fatty acids (PUFA), which enhance consumer fitness, are among the essential exported components. The patterns and drivers of dietary exports from ponds via insects remain poorly known, particularly at continental scales. We analyzed the exports of biomass, lipid, and fatty acid contents from emerging insects, sampled in 36 ponds across 11 European countries, from 36°N to 59°N and from 26°W to 19°E, over four seasons. We found that biomass and fatty acid exports decreased with increasing latitude and were higher in spring and summer. Seasonal effects also increased with higher latitudes. Temperature was the most important predictor of insect biomass, explaining 27.6% of the total variation and showing an unimodal response. Thus, increasing temperature may promote exports in colder regions and seasons but may negatively influence biomass exports in already warm regions. The exports of total lipids, PUFA, and eicosapentaenoic acid were correlated to exported biomass, while those of docosahexaenoic acid were linked to the emergence of Chaoboridae. Our findings indicated that PUFA contents were affected by taxonomic insect community composition and pond trophic state (indicated by chlorophyll a). Two of the correlates identified here (temperature and trophic state) are influenced by anthropogenic activity via climate and land use change, respectively. Thus, human activity impacts the food webs in and around ponds by influencing the quantity and quality of nutritional exports
Chapter 11 - Bioelectrochemically assisted constructed wetlands: the METland concept
No full texthe METland approach is an innovative combination of microbial electrochemical technologies (METs) and constructed wetlands (CWs) that can significantly enhance wastewater treatment and pollutant removal. Rather than using gravel, METland employs a biocompatible electroconductive material to encourage the growth and metabolism of electroactive bacteria. By utilizing an electroconductive bed designed in a short-circuit mode, this system can effectively remove pollutants through the microbial metabolism process without requiring an external circuit. Additionally, the METland’s remarkably low land footprint (0.4 m2/pe) sets it apart from traditional CWs, due to the high pollutant removal rate achieved by these microorganisms
Modular bioelectrochemical wetland: A demonstration study for treating urban wastewater
No full texthe integration of microbial electrochemical technologies (MET) into treatment wetland (TW) led to a new generation of nature-based solution so-called METland®. In this context, METland® concept was further expanded to modular METland® while a comprehensive evaluation of a demo scale is reported for the treatment of real domestic wastewater. The overall treatment system included the following METland biofilter configurations: i) a horizontal flow modular unit, ii) a downflow unit made of EC coke, and iii) a downflow unit made of EC biochar. This hybrid treatment system aims to enhance pollutant removal efficiency through MET, leveraging the conductive properties of substrates to optimize microbial metabolic processes. The system exhibited high COD removal efficiency (>90 %) regardless of high feeding rate (ca. 0.5m3/m2day) and significant nitrogen removal, with the EC biochar-based biofilter (ECBB) unit showing high ammonia removal efficiency (90 %). Standard treatment wetlands do not incorporate tools for monitoring the in situ performance of the systems. However, the electrochemical nature of the METland® allows continuous monitoring by measuring electrochemical parameters. In this context, electric potential (EP) measurements revealed spatial variations in electron utilization within the wetland, correlating with pollutant degradation. The electron current density (J = 43.99 mA/m2) within the system decreased along the flow path, indicating a consistent electrochemical activity aligned with the treatment process. High correlations between J values and COD concentrations suggest the potential use of electrochemical indicators as proxies for pollutant levels in wastewater treatment. This study gives insights into the electrochemical behavior of the system to provide a foundation for future optimization
Microbial electrochemical biosensor for real-time in situ hydrocarbon detection in groundwater
No full textMicrobial electrochemical biosensor for real-time in situ hydrocarbon detection in groundwate
Movilidad de microplásticos en suelos agrícolas procedentes de enmiendas con lodos de depuradora
No full textLa aplicación de lodos de depuradora como enmienda orgánica en el medio agrícola supone una fuente de microplásticos (MP) en el suelo. El objetivo de este estudio ha sido caracterizar los MP y determinar su movilidad con el agua cuando están presentes en el suelo como consecuencia de la aplicación de lodos. Para ello, se han utilizado sistemas que simulan agroecosistemas bajo 2 escenarios: i) suelo enmendado con lodo y ii) suelo enmendado con lodo donde se cultiva alfalfa. Los resultados demuestran que los MP quedan retenidos mayoritariamente en el suelo. Los MP movilizados por escorrentía son 1-2 órdenes de magnitud superiores que por infiltración, a pesar del mayor volumen de agua infiltrada. La presencia de alfalfa disminuye notablemente la cantidad de MP movilizados. La mayor parte de las partículas encontradas en todas las matrices son fibras de poliéster, seguidas de fragmentos de polietileno, polipropileno y poliestireno
A Paradigm Shift in End-of-Life Membrane Recycling: From Conventional to Emerging Techniques
No full textThe conventional linear life cycle of membrane materials, spanning fabrication, use, and disposal through landfilling or incineration poses serious sustainability challenges. The environmental burden associated with both the production of new membranes and the disposal of end-of-life (EoL) modules is considerable, further intensified by the reliance on fossil fuel-derived polymers, toxic solvents, and resource-intensive manufacturing processes. These challenges underscore the urgent need to integrate sustainability principles across the entire membrane life cycle, from raw material selection to reuse and regeneration. Emerging approaches such as membrane regeneration using recyclable polymers based on covalent adaptable networks (CANs) have introduced a new paradigm of closed-loop design, enabling complete depolymerization and reformation. In parallel, more conventional strategies, including the valorization of recycled plastic waste and the upcycling or downcycling of EoL membranes, offer practical routes toward a circular membrane economy. In this review, we consolidate current advances in membrane recycling, critically evaluate their practical constraints, and delineate the technical and environmental challenges that must be addressed for broader implementation. The insights presented here aim to guide the development of next-generation circular membrane technologies that harmonize sustainability with performance
Selective transport of Zn2+ through liquid and solid membranes containing pyrazole-tetrazole hybrid carriers
No full textBoth liquid (ML) and solid (MS) membranes bearing a pyrazole-tetrazole hybrid molecule as carrier are developed. The ML membrane is composed of CH2Cl2 solution inserted between an aqueous solution of metal nitrate, as a source phase, and a receiving phase containing deionized water. The MS membrane was prepared by photopolymerisation of pyrazole-tetrazole monomer and a polyacrylonitrile support. Being thermally stable up to 330 °C, the MS membrane exhibits an asymmetric amorphous structureIt was found that both membranes selectively transport Zn2+ over Cu2+, Pb2+, Cd2+, and Co2+ cations. At 25 °C and neutral pH, the permeate flux of Zn2+ reached 6.1 10-4 mol.h�1.m�2 for the ML membrane and 1.88 10-2 mol.h�1.m�2 for the MS membrane. Although the MS membrane exhibits more efficient Zn2+ permeate flux and higher stability than those of the ML membrane, the selectivity to Zn2+ transport of the MS membrane was found to be lower